Paraffin cutter



Feb. 24, 1942.

C. H. SWEET PARAFFIN CUTTER Filed Feb.

Patented Feb. 24, 1942 4UNITED STATES PATENT -oFFlcE Applicatilellr:reyet1,0;e4,aol 318,336

2 Claims.

My invention relates to a simple device for removing from an oil production tube of a well, wax' which has accumulated therein, and relates in particular to a device of this character which may be put into use and may be used without necessity of shutting down or materially interfering with the production of oil from the well.

In certain oil producing districts, the oil is found to have a waxy constituent, such as parailln, which tends to accumulate on the interior walls of a tube or casing set in the Well and through which tube or casing oil is owing from the well. Such tube casing or string of pipe is hereinafter referred to as the oil production tube of the well. The layer of wax f gradually builds up on the interior of the production tube so as to gradually reduce the production from the well and to finally completely choke off the production.

It is an object of my present invention to provide a simple device for periodically removing wax from the interior wall of the production tube, this device being hereinafter referred to generally as a paraiiin cutter.

It is an object of the invention to provide a device of this character which may be maintained in a substantially inoperativel condition in the upper part of the oil production tube, and may be periodically moved from its position-of rest, without necessity of shutting down the flow from the well, to remove such quantity of parafn from the wall of the casing or production tube as to maintain production at a near maximum value for given conditions of operation.

It is an object of the invention to provide a device of the above character which does not require an assembly of rods or tubes for its operation, thereby avoiding the necessity for use, as customary at the present time, of a string of pipe of smaller diameter than the production tube, run down into the production tube from the upper end thereof and with a parafiin remover on its lower end.

It is an object of the present invention to provide a paraffinv removing device having a cutter and means disposed below and connected to the cutter for moving the same downward lin the production tube so as to remove paraffin from the inner Wall thereof.

It is'a general characteristic of wells of the character hereinbefore referred to that the paraffin deposits on the inner wall surface of the production tube in a zone intermediate the upper and lower ends of the production tube. It is an object of the present invention to provide a parailin cutter or remover adapted to be moved through the zone of parain deposition inl the production tube so as to remove paraffin from this zone, means above and below the zone of paraln deposition for moving the cutter through the zone, such motivating means each including separate extension elements, each being preferably greater in length than the vertical dimension of the zone of paraflin deposition. Such extension elements may be conveniently made of small chain wire or cable as will be evident from the detailed description hereinafter written.

It is a further object of the invention to provide a device of the above character having a parailin cutter preceded by a group of scriber elements or knives, which scribe or out the deposited wall of paraiiin along vertical lines so that the action of the paraiiin cutter will be facilitated.

It is a further object of the invention to provide a parailin removing device of the character described which may be normally locked in the upper part of the production tube and which has. as motivating means therefor, a suspended weight element comprising a plurality of relatively small weights flexibly connected in serial relation.

Further objects and advantages of the inven tion will be brought out in the following part of the specification.

Referring to the drawing which is forl illustrative purposes only:

Fig. l is a sectional, partly sectioned schematic 'iew showing a preferred form of my invenion.-

Fig. 2 is an enlarged sectional view of the parailin cutter.

Fig. 3 is an enlarged cross-section taken as indicated by the line 3 3 of Fig. 2.

Fig. 4 is an enlarged cross-section taken on the line l--4 of Fig. 2.

In order to show an environment in which my invention may be advantageously employed, I have in Fig. 1 schematically pictured a well casing I0 which extends down into an oil producing formation II. The casing I0 is shown with a cap I2 from which an oil production tube I3 is suspended in such manner that an inlet strainer I4 at its lower end will be in a position to receive oil from the production zone of the well.

Screwed on to the upper end of the production tube I3 I have shown a cross-fitting I5 from which piping I6 for carrying off the production from the well is extended in the customary manner. The upper end of a production tube I3 pipe I3.

As shown to enlarged scale in Fig. 2, the member I8, which will be hereinafter referred to as the paramn cutter, comprises a cylindrical wall having upwardly and downwardly faced cutting or scraping edges and 2|, this member I8 being f such diameter that the/edges 2I will be spaced a reasonable working distance from the inner surface of the production tube I3. For example, in a production tube of substantially 2 inch internal diameter, a clearance of oneeighth of an inch may be provided between the edges 20 and 2| and the wall of the production tube I3. Means for engagement or operation are provided the tubular cutter I8 in the form of upwardly and downwardly extending balls 23 and V24, the legs of which may be suitably brazed or welded at 25 to the inner surface of the cutter I8. A bar element 26 is extended upward from the cutter I8 and is connected thereto by engagement with the bail 23, this bail having connected to its upper end a slender extension element 2l which may comprise a wire line or light weight cable which will serve as a suspension means for the cutter I8 during its downward movement through the production tube I3 and as a lifting means during the upward movement of the cutter I8. The bar 26 has a transverse opening 28 to receive a locking pin 28, for holding the cutter I8 in the chamber I'I during the periods of inoperation. as will be explained in the following.

As shown in Fig. l, a stuiiing box 30 is connected to the upper end of the production tube I3, this stufilng box having an axial opening 3| and a packing gland 32 through which the bar 28 extends to the exterior of the production tube. When the bar 26 is pulled up through the stuffing box 38, the pin 29 may be passed through the opening' 2,8, as shown in dotted lines 29a, in a position above the gland nut 33 of the stuiling box 38, thereby supporting the cutter I8 and its associated elements in raised, or inoperative position. When the cutter I8 is supported in inoperative position, the packing gland 32 serves to prevent escape of oil from the upper end of the production tube I3 around the bar element 26- and the suspension means. When it is desired to lower the cutter I8 within the tube I3, a cable packing device 35 is screwed on to the upper end of the stuffing box 38 after removal of the pin 28 from its position 29a, the load at this time being taken by the suspension element 2l which extends through a packing gland 36 forming the upper part of the member 35.

A feature of my present invention is the provision of means below the cutter I8 to apply a downward force to move the cutter downward under control of the suspension means comprising the member 21 which may extend to and be wound upon a drum, not shown in view of the common practice of drum and cable usage in oil well equipment. I accomplish this purpose by the provision of a weight element 38 which is connected to the cutter I 8 through use of a slender extension element 38, which may be a wire of slightly less than one-eighth of an inch diameter, depending upon the weight to be supported thereby. Although al1 practices of my invention do not require the same, I provide in conjunction with the cutter I8 a scoring or scribing means 40 comprising a supporting bar 4| which is connected to the cutter Il by means of the lower bail 24, this'bar 4I having thereon a plurality of scoring or scribing blades 42. Disposed at diilerent angles so that as the member l 48 moves downward through the portion oi' the production tube I3 having aninternal coating of wax or paramn thereon, such coating will be scored as indicated in dotted lines 43 in Fig. 4. The slender extension element 38 is connected to the lower end of the bar 4I and to the upper end of the weight element 88 which comprises a plurality of weight sections 45 connected together in a flexible manner by links 48. The purpose of making the weight element 38 sectional instead of as a single bar of considerable length, is to avoid the possibility of breaking the strainer I4 at the lower end of the production tube I3 should the weight element 38 be lowered to such an extent as to be brought into engagement with the strainer I4. It will be perceived that as the strainer I4 is engaged, asthe result of lowering the weight element 38, the blow which isstruck thereagainst will be Iinitiallythat which is due to the weight of the lowest weight section 45, instead of av heavy blow which` would result if the sections 45 were formed rigidly into a single,

bar.

In Fig. l I show a portion I3a of the production tube I3 lying in the zone of parailin deposi-.

tion, and accordingly show a wallor layer of parafiin built up on the interior thereof; It is a feature of the invention to make the slender extension element 38 of such length that it willy pass through the restricted opening.5I formed by the layer 50 and support the -weight element 38 in the production tube I3 below the zone of parailln deposition. Being thus supported below the zone of parafiln deposition in the production tube I3, the weight element 38 is free to move downward as the cutter I8 and the associated scoring and scribing means I4 are lowered, and such weight element will be capable of exerting sufcient downward force to move the cutter I8 down through the zone of deposition to scrape or slice off a material portion of the accumulated paratlin, which will be carried out of the upper end of the production tube I3 by the upward flow of oil. The vertical cutting or scribing of the layer of parafhn 58, as indicated in dotted lines in Fig. 4, facilitates the breaking upof the paraiin in such a manner that it may pass-readily upward through the axial opening of the cutter I8 and thence upward through the production tube I3 and the outlet pipe I6 to a suitable point of disposal.

Ay single round trip of the parailin removing means disclosed is suillcient to accomplish the desired result, and in view of the simplicity of operation of the device, the cutter` I8 may be passed through a round trip at frequent intervals, thereby maintaining the production of the well at a mere maximum value, instead of waiting until the flow from the well is shut off 'completely, or nearly so, before cleaning out the accumulated paraffin. l

I claim as my invention:

l. A wax cutter for use in the oil kproduction tube of a owing well subject to wax deposition duction tube above the zone of wax deposition, and a slender elongated element extending from :aid bar downwardly through the zone of wax deposition and having a weight vsecured to its lower end, saidsuspending means being adapted to lower said cutting assembly by virtue of the effect of said weight through the zone of wax deposition whereby the wax is substantially removed and is carried upwardly to the surface by the now of oil through the oil production tube.

2. A wax cutter for use in the oil production tube of a owing well subject to wax deposition in a zone therein comprising a wax cutting assembly embracing an annular ring of slightly less external diameter than the internal diameter of the oil production tube and an elongated bar del duction tube.

pending therefrom provided with a plurality of radially extending blades, means for suspending said parailin cutting assembly in the oil production tube above the zone of wax deposition, and a slender elongated element extending from said bar downwardly through the zone of wax deposition and having a plurality of spacediiexibly connected weight elements secured lto its lower end, said suspending means being adapted to lower said cutting assembly by virtue of the effector said weight elements through the zone of wax deposition whereby the wax is substan-v tially removed and is carried upwardly `to the surface by the flow of oil through the oil pro- CECIL H. SWEET. 

